This proposal is a request for continued partial funding of the Flow Cytometry Core Facility (FCCF) within the Multipurpose Arthritis & Musculoskeletal Disease Center (MAMDC). The primary purpose of the FCCF is to make available to MAMDC investigators access to the equiment, trained personnel and expertise to perform cell analysis and purification with state-of-the-art equipment and techniques on a reasonable cost for services basis. The FCCF serves over 120 individuals per year. Although the FCCF is open to all UAB researchers, service to MAMDC investigators accounts for approximately 80% of center operations. At the present time the FCCF contains a FACScan five parameter single laser analytical cytometer and a FACStar(plus) six parameter, dual laser cytometer/sorter. The computers which control these instruments have been networked for efficiency, and a variety of programs for univariate through tetravariate fluorescence analysis, DNA curve fitting, immune monitoring and numerous other applications are available. The MAMDC FCCF and the University of Alabama AIDS Center Flow Cytometry Facility are operated jointly. This results in improved service to investigators through increased flexibility in equiment and personnel. Disruption due to equipment maintenance or leave of absence of personnel are minimized. The facilities jointly employ an Associate Core Director (MLS) and a lab manager (GQH) who are both experienced cytometer operators. Funds are requested to ensure stable support for 50% of the operators' salaries for the operators, and to cover a portion of the field service contracts for the cytometers. The requested level of support will be sufficient to cover approximately 50% of the actual cost of operating the FCCF. This will allow the present rate of $50/hour for MAMDC investigators to be sustained into the foreseeable future.